[whatwg] Canvas pixel manipulation and performance

[Jason Oster]

On Nov 29, 2009, at 1:57 PM, Boris Zbarsky wrote:
> So the new code has to do about half as much tile decoding, as well as half the number of imagedata[n] sets?  Or was the decoding already being cached?
Decoded tiles were already cached.  It actually builds MORE tile caches now, though: one cache for each this.fgmap[].  So that's more (a lot more) tile decoding, but far fewer pixel pokes.